The invention relates in general to manual die sets for pressing explosive powder and in particular to manual die sets for pressing explosive powder into hardware.
For some munitions applications, it is desirable to have explosive powder encased in hardware, such as a cup. The cup is a hollow tube with a closed bottom and is made of, for example, aluminum or an aluminum alloy. The explosive powder is a highly sensitive explosive molding powder, for example, PBXN-9 or PBXW-11. The explosive powder is poured into the cup and the cup is inserted into a die. A ram presses the explosive powder in the cup to form a pellet in the cup. The ram is then retracted, and the cup with the explosive pellet therein removed from the die. A set of crimping tools is used to close the top opening in the cup.
A particularly dangerous part of the above-described procedure is retracting the ram from the cup. The inside diameter of the cup is generally about 0.003 to 0.005 inches larger than the outside diameter of the ram. The cup retains explosive powder residue on its internal surfaces. As the ram is retracted, it is possible that friction between the ram and the powder residue on the inside of the cup way cause the powder residue to ignite and explode, and, in turn, cause the pressed powder to ignite and explode. Therefore, it is necessary that any humans be far enough away from the retracting operation to avoid injury or death if the powder explodes.
Although humans possess the strength required to retract the ram from the cup, the danger of explosion absolutely prohibits a human from manually retracting the ram from the cup. Therefore, "fixed" die sets have been used to press explosive powder into hardware, such as a cup. In the fixed die set, the ram is rigidly connected to the pressing device. The pressing device is, for example, a 100 to 200 ton hydraulic press. The press is remotely controlled so that the human operator is out of the zone of danger, should an explosion occur. The fixed die set is safer for the operator, but there are some disadvantages of using a fixed die set.
First, much time is required to manufacture the tooling to fix the ram to a press. Second, because different models of presses may be used, different tooling for each press is necessary. Third, after the ram is attached to the press, the press is "dedicated" to a single operation, until the ram is removed. Fourth, much time is spent aligning the ram that is attached to the press to the die. Last, different lengths of ram travel are necessary for different amounts of explosive powder used. Thus, the fixed die set and/or press must be adjusted whenever a different length of ram travel is desired.
The present invention is a manual die set that overcomes the disadvantages of the fixed die set while maintaining the safety of the human operator.